You may use the following ways to add files, e.g. PDF, onto your Mendeley Desktop:
1. Add Files
2. Drag and Drop
3. Watch Folder
Mendeley uses a web importer Save to Mendeley for adding online resources to your Mendeley library. In order to get this function work, you should firstly go to the Mendeley website, drag from this webpage to the bookmarks bar of a web browser.
Sometimes the Web importer will be unable to read any data. In this case you will be prompted to manually add details to the record.
On Mendeley desktop, click the dropdown menu of Add Files, select Add Entry Manually, type details of a book or an article into the fields.
Some files or references added to the library do not include full details. For example, the details of authors and the journal are missing from the following reference record. We can manually add details to these fields.